Six Improved Cameroonian Potato Varieties Introduced In Vitro Through Meristem Culture

Introduction:Availability of disease-free, high yielding potato planting material is a major challenge to producers. This study focused on evaluating the ability of locally improved varieties to be introduced for the first time in vitro. Meristem tip culture was used to regenerate in vitro plantlets from improved potato varieties in Cameroon. Materials and methods: Six varieties including Cipira, Mafo, Jacob 2005, Bambui Wonder, Tubira and Irad 2005 were taken from IRAD potato breeding program. Ten meristems were cultured per replicate (4) per variety.The number of meristem tips sprouting, rooting, the number of nodes and shoot length were recorded weekly over a period of 4 weeks. Results and discussion: Meristem tips of all potato varieties regenerated plantlets with vigorous shoots and roots. Sprouting began in the first week and ranged from 40% (Tubira) to 75% (Cipira and Jacob 2005). Rooting began in the 2nd week and ranged from 7.5 % (Cipira) to 37.5 % (Irad 2005 and Tubira). Regenerated shoots of all varieties had nodes averaging from 10.0 to 12.5, thus ready for micro-propagation. Conclusion: All six improved potato varieties can be introduced in vitro for rapid multiplication of planting material. Regenerated plantlets should be serologically tested to check they are free from diseases especially viruses

An Alternative Tissue Culture Media for Potato (Solanum tuberosum L.) Micro Propagation

The cumbersome nature of tissue culture technique contributes to the low adoption of the technique. This work aims at developing an accessible alternative tissue culture medium for potato micro propagation. The inorganic components of the conventional MS medium were replaced with a common source of nitrogen, phosphorus and potassium (NPK) to regenerate in vitro plantlets of six improved Cameroonian potato varieties selected from meristem-derived plantlets. These varieties included: Cipira, Mafo, Bambui wonder, Irad 2005, Jacob 2005 and Tubira. Five (5) nodes each per replicate per variety were cultured on both media and allowed to grow at a temperature of 21 ºC and 16hrs/day photoperiod for 28 days.Number of nodes sprouting, number of nodes rooting, plant height, and number of nodes per plantlet were recorded weekly in 4 weeks. Results shows that both media regenerated vigorous plantlets with shoots and roots. Using the Statistical Package for Social Science (SPSS), analysis of variance revealed slight significant differences (p≤0.05) between varieties and media in terms of sprouting and rooting Height of plantlets on NPK medium ranged from 29.85 mm (Cipira) to 45.25 mm (Irad 2005) meanwhile, on MS medium it ranged from 47.93 mm (Bambui Wonder) to 65.70 mm (Jacob 2005). Average number of nodes ranged from 2.59 (Tubira) to 3.63 (Mafo) on fertilizer medium while on MS medium it ranged from 2.70 (Irad 2005) to 4.20 (No significant difference at p≤0.05). in conclusion; the developing countries can replace the inorganic components of MS medium with inorganic fertilizer (NPK) for in vitro multiplication of potato

Reactions of some potato genotypes to late blight in Cameroon

Field experiments were conducted in Cameroon in 1995 and 1996 to evaluate reactions of different potato genotypes to late blight. There were significant differences among genotypes for tuber yield, late blight readings and earliness. The application of fungicides significantly increased potato yield but had a non significant effect on the damage due to foliage blight (Phytophthora infestans). The limited effect of fungicide treatment was because the late blight severity was so high that the eight fungicide applications could not provide sufficient level of disease control and/or the persistence rain throughout the growing season might have washed-off the applied fungicide, thus decreasing its effect. There was a significant year effect on the yield. The fifth late blight reading (LB5) was more related to yield than the later readings suggesting that the damage caused by the disease at an earlier stage of plant development contributed most to yield reductions. Several advanced genotypes had similar or superior performance to that of CIPIRA and TUBIRA released in Cameroon in 1992. Key Words: Cameroon, Phytophthora infestans, potato yield, Solanum tuberosum (African Crop Science Journal 2001 9(1): 209-214

Prevalence of Six Viruses in Potato Seed Tubers Produced in Informal Seed System in the North West Region of Cameroon

Potato (Solanum tuberosum L.) is an important cash-food crop, which is widely grown in three of the five agro-ecological zones of Cameroon. A study was carried out to determine the prevalence of PVA, PLRV, PVM, PVS, PVX and PVY in 1175 sprouted potato seed tubers of different diameters collected from four seed stores in the North West Region of Cameroon. The study also sorts to ascertain variations in virus incidence in small, medium and large size sprouted tubers prior to planting. The DAS-ELISA method was used to test for the presence of these viruses. Results showed significant differences in the prevalence of the six viruses with PVM being the most prevalent (92%), while PLRV was least prevalent (35%) in all the four seed stores sampled.  Upper-Farm store registered the highest relative prevalence (82%), with PVM detected in all the tubers while samples from Rock-Farm store showed the least relative incidence (55%) with no PLRV detected. Viruses were significantly most prevalent in small size tubers (71%) and least in large size potato tubers (63%). Our results suggest that tuber size can serve as a guide to identify healthy (virus-free) tubers. Farmers could therefore use large size potato tubers for planting